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European Union Legal Materials


This section covers developments in the EU, including the enlargement process, the introduction of the Euro, and the Constitution of the EU and the Treaty of Lisbon.

Overview of enlargement

The EU has expanded multiple times since its inception.

In May 2004, ten new countries joined the European Union, bringing the number of member states to twenty-five. Since this enlargement included many Eastern European and Baltic countries, it has greatly expanded the geographic scope of the EU, as well introducing many new official languages. In 2007, Bulgaria and Romania joined the European Union. On July 1, 2013, Croatia joined the EU.

This process of countries joining the EU is often referred to as enlargement. Countries who wish to join the EU must meet the necessary membership criteria. There are 3 stages in the process of enlargement, which is subject to approval by all EU countries: (1) Becoming an official candidate for membership (2) Undergoing formal membership negotiations (3) Completion of negotiations and accompany reforms to the parties' satisfaction and joining the EU.

Further enlargement is still being planned. With the war in Ukraine, Kyiv has asked for a fast-track procedure of EU membership. The EU has also started accession negotiations with the candidate countries, Albania, North Macedonia, Montenegro, Serbia and Turkey. You can find more information about the negotiation status of candidate countries here.

Resources related to enlargement

To see more background and reference works available at Diamond Law Library, including older editions, see here.

The Euro

On January 1, 1999, the European Union implemented the Euro as a single economic unit and on January 1, 2002, paper and coin Euros came into circulation. Adopting the euro allows the economies of the "Euro-area" members to become more integrated. Currently, 19 of the 27 current EU members have adopted the Euro as their official currency and are part of the Euro Area. The most recent country to adopt the Euro is Lithuania, which adopted it in 2015. The remaining non-Euro-area member states were those who acceded to the Union after the euro was launched, but did not meet the necessary conditions for entry to the Euro-area and are considered "Member States with derogation".

The Constitution for the European Union and the Treaty of Lisbon

Between February 2002 and July 2003, the Convention on the Future of Europe took place with the intent of developing a draft constitution for the EU. The Draft Constitution was completed and presented to the President of the EU by the President of the Convention on July 18, 2003. The final version of the proposed constitution, called the Treaty Establishing a Constitution for Europe, was signed by the heads of state on October 29, 2004. It was submitted to the member states for ratification. Although it has been ratified by fifteen countries, the Treaty was defeated in France and the Netherlands in June 2005. Following those defeats, the European Council decided to review the constitution and the ratification process in early 2006. In their June 2006 meeting, the European Council extended the period of review and reflection for another two years.

After this period of review, the Treaty of Lisbon was signed on December 13, 2007 and entered into force on December 1, 2009. The Treaty of Lisbon replaces the Constitution.

Resources related to the Treaty of Lisbon and the Constitution